Sun Yat Sen Univ, State Key Lab Optoelect Mat & Technol, Sch Chem & Chem Engn, Guangzhou 510275, Peoples R China
; Chinese Acad Sci, Changchun Inst Appl Chem, Lab Rare Earth Chem & Phys, Changchun 130022, Jilin, Peoples R China
; Chinese Acad Sci, Lab Beijing Synchrotron Radiat, Inst High Energy Phys, Beijing 100039, Peoples R China
The optical properties of rare earth ions-activated barium orthophosphate phosphors, Ba-3(PO4)(2):RE (RE = Ce3+, Sm3+, Eu3+, Eu2+, and Tb3+), were investigated in vacuum ultraviolet (VLTV)-Vis range. A band-band transition Of PO43- in Ba-3(PO4)(2) is observed in the region of 150-170 nm. The partial reduction of Eu3+ to Eu2+ was observed and confirmed by luminescent spectra under the VUV-UV excitation. It is proposed that the electronegative defects that formed by aliovalent substitution of Eu3+ on the Ba2+ site in the host are responsible for the reduction process. (C) 2003 Elsevier Science Ltd. All rights reserved.